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These improvements not only willincrease the operational capability of the ship but also are anticipated to lower the ship’s manpower requirements and maintenance costs.Under current for

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MODERNIZING THE U.S AIRCRAFT CARRIER FLEET

Accelerating CVN 21 Production

Versus Mid-Life Refueling

John Schank Giles Smith Brien Alkire Mark V Arena John Birkler James Chiesa Edward Keating Lara Schmidt

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Library of Congress Cataloging-in-Publication Data

Modernizing the U.S aircraft carrier fleet : accelerating CVN 21 production versus

mid-life refueling / John Schank [et al.].

p cm.

Includes bibliographical references.

“MG-289.”

ISBN 0-8330-3720-X (pbk : alk paper)

1 Aircraft carriers—United States—Design and construction I Schank, John F (John Frederic), 1946–

USS Ronald Reagan Exiting the Straits of Magellan.

The research described in this report was prepared for the United States Navy The research was conducted in the RAND National Defense Research Institute, a federally funded research and development center supported by the Office of the Secretary of Defense, the Joint Staff, the unified commands, and the defense agencies under Contract DASW01-01-C-0004.

Preface

The U.S Navy is currently designing the next generation aircraft rier, the CVN 21 This class of carriers will use the same basic hull

car-form as the current Nimitz class but will include a substantial

rede-sign of the interior of the ship for improved weapons handling andstores management functions It will also incorporate several newtechnologies, including a new propulsion plant and new aircraftlaunch and recovery systems These improvements not only willincrease the operational capability of the ship but also are anticipated

to lower the ship’s manpower requirements and maintenance costs.Under current force modernization plans, new ships of theCVN 21 class will be introduced every four or five years as the ships

of the Nimitz class reach the end of their planned 50-year operational life Under this strategy, Nimitz-class carriers will be operating for

more than 50 more years and it will take decades to transform theaircraft carrier fleet to ships of the new class

On the basis of some preliminary calculations that appearedpromising, the RAND Corporation proposed to the ProgramExecutive Office (PEO) for Aircraft Carriers an examination of a way

to accelerate the transformation of the carrier force: replacing

Nimitz-class carriers as they reach midlife instead of refueling them In thisreport, we identify specific fleet management options for buildingnew instead of refueling, and we evaluate their advantages anddisadvantages This report should be of interest to Navy and Office ofSecretary of Defense planners examining fleet modernization options,

iv Modernizing the U.S Aircraft Carrier Fleet

especially those organizations addressing the costs of alternative forcestructure options

The research documented in this report was carried out withinthe Acquisition and Technology Policy Center of the RANDNational Defense Research Institute, a federally funded research anddevelopment center sponsored by the Office of the Secretary ofDefense, the Joint Staff, the unified commands, and the defenseagencies

For more information on RAND’s Acquisition and TechnologyPolicy Center, contact the Director, Philip Antón He can be reached

by e-mail at atpc-director@rand.org; by phone at 310-393-0411,extension 7798; or by mail at the RAND Corporation, 1776 MainStreet, Santa Monica, California 90407-2138 More informationabout RAND is available at www.rand.org

Contents

Preface iii

Figures vii

Tables xi

Summary xiii

Acknowledgments xxiii

Abbreviations xxv

CHAPTER ONE Introduction 1

CHAPTER TWO Fleet Modernization Options and Their Implications for Fleet Size and Composition 5

Today’s Policy: The Reference Case 6

Scheduled Refueling and Maintenance 6

Fleet Composition and Size 11

A Nominal Build-New Strategy 14

Other Build-New Options with a 22-Year Unrefueled CVN 21 Life Span 17

A Build-New Option with Unrefueled CVN 21 Life Span Extensions 23

CHAPTER THREE Adequacy of the Industrial Base 27

NGNN 28

Production Facilities 29

vi Modernizing the U.S Aircraft Carrier Fleet

Workforce 34

Management Functions 40

Vendors 41

Nuclear 41

Nonnuclear 42

Navy 45

Conclusion 46

CHAPTER FOUR Life-Cycle Cost Analysis 47

Approach 47

Modeling LCC 50

Metrics for Comparison 51

Baseline Comparison 52

Comparison of All Alternatives 53

Cost Reductions from Other Sources of Savings 56

Sources 57

Cost Reductions 60

Other Considerations 62

Impact on Other Programs 62

Extended Core Life 63

Defueling and Demilitarization 64

Summary 64

CHAPTER FIVE Synthesis 65

APPENDIX A CVN 21 Design and Technology Advances 75

B Shipyard Production Labor Demand by Skill 85

C How Life-Cycle Cost Elements Were Estimated 89

Bibliography 97

Figures

S.1 A Build-New Strategy Can Modernize the Fleet Twice

as Fast xiv

S.2 A Build-New Plan Sustains at Least as Many Operational Ships and Almost as Many Total as the Navy’s Current Plan (Reference Case) xv

S.3 Increasing the Production Interval to 24 Months Costs an Extra 12 Percent xvi

S.4 Aggressive Cost Reduction Can Cut the Nominal Build-New Cost Premium in Half xix

S.5 Build-New Options with a 24-Month Production Interval Generate Greater “Fleet Value” than the Reference Plan or 30-Month Plans xx

S.6 Build-New Strategy Requires Managing a Labor Demand Peak Until 2017 xxi

2.1 Operational Life Course of Nimitz-Class Carriers 9

2.2 Comparison of Nimitz-Class and CVN 21 Life Spans 10

2.3 Evolution of Fleet Composition for the Reference Case 12

2.4 Fleet Modernization Profile for the Reference Case 13

2.5 Fleet Size for the Reference Case, 2010–2050 13

2.6 Assumed Life Cycle of Nimitz- and CVN 21–Class Carriers for the Build-New Strategy 14

2.7 Evolution of Fleet Composition for the Nominal Build-New Case 15

2.8 Fleet Size Sustained by Nominal Build-New Strategy, 2010–2050 16

viii Modernizing the U.S Aircraft Carrier Fleet

2.9 Fleet Modernization Rate, Reference Case Versus Build-New Strategy 17 2.10 Fleet Size Sustained by Build-New Strategy with Extended New Start Interval (30/72) 19 2.11 Fleet Modernization Rate, Reference Case Versus 24/72 and 30/72 Options 20 2.12 Fleet Size Sustained by Build-New Strategy with No RCOH After CVN 71 (24/71) 21 2.13 Fleet Size Sustained by Build-New Strategy with Combined Cost- Saving Variants (30/71) 22 2.14 Two Hypothesized Extended Unrefueled Life Cycles for CVN 21– Class Ships 23 2.15 Fleet Size Sustained by 30-Month Build-New Interval and 26- Year Unrefueled Life Span 24 2.16 Ship Life Sustained by 30-Month Build-New Interval and 30- Year Unrefueled Life Span 25 3.1 Workload Profile for CVN 21 Construction and RCOH 35 3.2 Total Shipyard Labor Demand for Reference Case and Nominal Build-New Option 36 3.3 Total Shipyard Workforce Demand for Alternative Carrier

Modernization Plans 37 3.4 Total Shipyard Outfitting-Labor Demand for Reference Case and Nominal Build-New Option 38 3.5 Total Shipyard Welder Demand After 2016 for Alternative

Shipyard Modernization Plans 40 4.1 Influence Diagram for LCC Elements 50 4.2 Cost Comparison, Reference Case Versus Nominal Build-New Option 53 4.3 Cost Comparison per Operational Ship-Year, Reference Case Versus Nominal Build-New Option 54 4.4 Annual Funding Premiums of All Build-New Options Relative

to the Reference Case 56 4.5 Reduction in Engineering Hours with Two-Ship Buys 58

4.6 Workforce Learning on the Nimitz Class 59 4.7 Effects of Other Sources of Savings on LCC, Nominal Build-New Option 60

Figures ix

4.8 Effect of Other Sources of Savings on LCC in All Build-New Options 61 4.9 Effect of Other Sources of Savings on LCC per Operational Ship- Year in All Build-New Options 62 4.10 Effect of Other Sources of Savings on Annual Funding Premiums

in All Build-New Options 63 5.1 Fleet Value of 24/72 Plan as Percentage Increment over Reference Plan for Different CVN 21 Capability Increments 69 5.2 Fleet Value as Percentage Increment over Reference Plan for Different Build-New Options 70 5.3 Fleet Value as Percentage Increment over Reference Plan for Different Build-New Options and Capability Ratios 71 5.4 Fleet Value as Percentage Increment over Reference Plan, for Different Build-New Options, No Discounting 72 C.1 Influence Diagram for LCC Elements 89 C.2 Budget Profiles for Carrier Acquisition, Relative to Year of Full Funding 94

Tables

S.1 Build-New Options with Best Cost Implications Have Worst Fleet

Size Implications xvii

2.1 Life Spans of Current Aircraft Carriers 6

2.2 Characteristics of Fleet Management Options Analyzed 18

2.3 Average Fleet Size for Build-New Options, 2010–2040 22

3.1 Times to Construction Milestones for Nimitz-Class Carriers 29

3.2 NGNN Facility Costs for Options Analyzed 33

4.1 Cost Comparison of Build-New Options with Reference Case 54

5.1 Fleet Size and Cost Effects of All Build-New Options 66

B.1 Maximum Rate of Change in Labor Demand 86

B.2 Mean Labor Demand from 2005 to 2025 86

B.3 Standard Deviation of Labor Demand from 2005 to 2025 87

Summary

The U.S Navy is currently building the last of the Nimitz class of

aircraft carriers The next ship to be started will belong to a new class,designated CVN 21 This new design will incorporate numerous

improvements over the Nimitz design Among the most important

will be improved weapons handling, a propulsion plant that will erate more electricity to support functions now controlled by steamand hydraulics, an electromagnetic aircraft launch system, and a gen-eral rearrangement to improve operations It is anticipated that thenew class of ship will require fewer personnel to operate and willspend less time in shipyard maintenance, both of which will contrib-ute to reduced operating costs

gen-The Navy’s plan is to continue building aircraft carriersapproximately once every four years Ships of the new class will

replace older ones that are retiring Nimitz-class ships are scheduled

to retire at approximately age 49, after two 23-year operational ods separated by a three-year midlife refueling and complex overhaul.This plan will transform the carrier fleet into one composed ofthe higher-performance, lower-cost CVN 21 ships at a very slow rate

peri-Even in 2035, half the fleet will be Nimitz-class ships.

We here propose a more rapid modernization plan: building

new aircraft carriers more often and retiring about half the

Nimitz-class ships at what would have been their midlife refueling point Wecompare several variations of this approach with a reference caseapproximating the Navy’s current plan Criteria for comparisoninclude rate of fleet modernization, average number of ships sustained

xiv Modernizing the U.S Aircraft Carrier Fleet

(total and operational), present value of acquisition and operatingcosts, and near- and midterm funding required Our central finding isthat the fleet can be modernized much faster, even twice as fast, for acost premium no greater than 12 percent That premium can bereduced through decreasing fleet size by 5 to 10 percent or possiblythrough aggressive cost reduction efforts We also find that the indus-trial base is adequate to support the higher production rate

The gain from a shorter interval between carrier productionstarts is depicted in Figure S.1, which shows the percentage of thetotal carrier fleet made up by the CVN 21 class as of the datesshown.1 If the time between new carrier construction starts ishalved—that is, if the production interval is dropped from the cur-

1 Note that we show the CVN 21 percentage reaching and staying at 100 percent However,

we assume in all our analyses that CVN 21–class carriers are also retired when their initial fuel load is exhausted and that they too are replaced by carriers (presumably a follow-on class) built new.

Summary xv

rent notional 48 months to 24 months, the fleet is modernized twice

as fast CVN 21s will make up the fleet majority 12 years earlier, andthe fleet will be transformed 22 years earlier

As shown in Figure S.2, a 24-month interval sustains a fleet that

is about half a ship short of the reference fleet in size However, thenumber of operational ships (those not in the shipyard) is at least asgreat as in the reference case This bonus emanates from the lowermaintenance requirements designed into the CVN 21 More CVN21s in the fleet mean more ships available for deployment or training.These benefits come at a cost Although the larger number ofCVN 21s in the fleet translates into lower personnel and maintenancecosts, the fleetwide savings are not large, particularly for personnel,for two reasons First, it still takes a number of years for the fleet to

evolve from a Nimitz-class fleet to a CVN 21 fleet; second, the

greater savings many years in the future are worth much less than

Figure S.2

A Build-New Plan Sustains at Least as Many Operational Ships and Almost

as Many Total as the Navy’s Current Plan (Reference Case)

NOTE: Reference case data displayed as dotted lines

xvi Modernizing the U.S Aircraft Carrier Fleet

their nominal value today—that is, they must be discounted more, a multibillion-dollar charge is incurred when an extra carrier isbuilt every fourth year Less than half those charges are offset by

Further-avoiding refueling a Nimitz-class ship If the various costs and savings

offsets in the construction, personnel, and operations and nance budgets are calculated for the 50-year period beginning in

mainte-2002, the net result is a cost premium for the build-new plan Thatpremium amounts to 12 percent, or $22 billion in present discountedvalue (see Figure S.3).2 The extra costs would manifest themselves as

an added $700 million annual budgetary requirement from 2005 to

2015 alone

We examined two approaches to reducing that cost premium.First, we varied the specifics of the build-new strategy Instead of 24months, we tried a 30-month interval, which would modernize the

Personnel Acquisition

2 For lack of data, our estimates do not include the cost of defueling and demilitarizing retired carriers, activities that will occur earlier and more frequently under the build-new plan than in the reference case Our cost premium estimate may thus be somewhat con- servative.

Summary xvii

fleet almost as fast as the 24-month option We tried retaining the

24-month interval but running one fewer Nimitz refueling (stopping

with CVN 71 instead of CVN 72) Finally, we analyzed an optioncombining these two variants

The results are shown in Table S.1 The first row under “AfterCVN 72” represents the nominal build-new plan and the other three

cells (where each cell comprises w /x y% (z%)) represent the three

alternatives just specified (further explanation follows)

The 30-month variants solve the cost problem The cost ums relative to the reference plan are near zero or even negative (seethe numbers outside parentheses on the right side of each cell inTable S.1) However, the variants have the effect of taking one ormore ships out of the fleet (see the numbers at the left under both the

premi-“After CVN 72” column and the premi-“After CVN 71” column; the totalreference fleet averages 12.1 ships) The penalty in operational shipsranges from almost nothing for the 24-month plan with one less refu-eling and complex overhaul (RCOH) to half a ship or more for the30-month plans (see the numbers on the left side of each cell, to theright of the slash; the reference fleet averages 8.4 operational ships).Our second approach to reducing the cost premium was toexamine several cost reduction measures:

• Multiship buys: The faster build schedule might promote ship contract packages that could lower costs for engineeringand for materials and equipment

xviii Modernizing the U.S Aircraft Carrier Fleet

• Learning: A faster build schedule could allow for lower costs onrepeated production tasks We assumed for the build-new strat-egy a slight advantage over the lack of learning we assumed(from historical precedent) in the reference case

• Additional crew reduction: The Navy postulates a crew

reduc-tion of as many as 800 for the CVN 21 versus the Nimitz class.

We adopted 800 as the reference case reduction and postulatedthat an additional 200 crew members could be removed withaggressive measures to reduce ship manning

• Outsourcing: We assumed a small increase in outsourcing overwhat is expected, for a modest labor cost savings on the workoutsourced

The cumulative effect of these savings on the original, nominalbuild-new plan are shown in Figure S.4 The relative effects of themeasures are in the order listed above, with multiship buys having thegreatest effect and outsourcing the least Together, these cut thebuild-new plan’s 12-percent cost premium by 7 percentage points, ormore than half Applying these measures to the variant build-newoptions also cuts their costs by 5 to 7 percent, as indicated by the par-enthetical numbers in Table S.1 We regard these cost reductionmeasures as ambitious but feasible By adopting them and by elimi-nating the CVN 72 RCOH (see top right cell in Table S.1), the Navycould modernize faster at hardly any cost premium

The trade-off between faster modernization and a smaller tional fleet can be quantified in terms of future operational CVN 21ship-years Those ship-years can then be multiplied by a factor indi-cating the ratio between a CVN 21–class ship’s capability and a

opera-Nimitz-class ship’s capability, and future operational opera-Nimitz-class

ship-years can be added in The result, which needs to be discountedfor comparison with discounted costs, is the present value of futureoperational ship-years, weighted to favor CVN 21–class ships: ameasure of the fleet’s value to the Navy The value is higher if thefleet converts more quickly to CVN 21s or if the number of opera-tional ships is typically larger

and crew reductions

and learning

and multiship

It was not within the scope of this report to predict a most likely

CVN-21:Nimitz capability ratio However, we examined several

pos-sibilities to get a sense of the fleet value premiums achievable If, forexample, the Navy were to view a CVN 21–class ship as 30 percent

more capable than a Nimitz-class ship, the nominal build-new plan

would result in a 7 percent fleet value premium over the referencecase (see Figure S.5) That is, the fleet would have an average opera-tional capability 7 percent higher (in discounted terms) than it would

if the reference plan were followed That may be compared with the

12 percent (or 6 percent) cost premium from Table S.1 Eliminatingthe CVN 72 RCOH, as noted above, virtually eliminates the costpremium if aggressive cost reduction is pursued Figure S.5 indicates

a fleet value premium of 4 percent Whether these are good ments or not depends on the importance the Navy attaches to fleetvalue premiums of those sizes

invest-xx Modernizing the U.S Aircraft Carrier Fleet

Figure S.5

Build-New Options with a 24-Month Production Interval Generate Greater

“Fleet Value” than the Reference Plan or 30-Month Plans

NOTE: CVN 21 capability increment = 30%

No industrial-base impediments hamper implementation of any

of the build-new options defined here A significant short-term sient in the shipyard labor profile occurs (see Figure S.6, 2017 andbefore), peaking at 24 percent over the reference plan This demandmust be managed, but the build-new strategy affords an opportunityfor greater long-term workforce stability (after 2017) This is true aswell for the variant build-new options, although for those both thepeaks and the long-run average demands are somewhat lower than inthe nominal build-new option

tran-Some facility upgrades are needed at the shipyard, but thereappear to be no critical problems there Suppliers of parts for thenuclear-propulsion plant will need to undertake some modestupgrades The challenge there, however, is not really capacity buttiming If a build-new strategy is to be implemented so that the sec-ond CVN 21–class ship is started in 2009, propulsion plant supplierupgrades must begin promptly (i.e., long lead item procurement must

Summary xxi

begin in FY 2005 to support an FY 2009 ship) Vendors of nuclear components are generally in place and capable of meeting thehigher production rate

Acknowledgments

Our work on this project was greatly facilitated by personnel at theProgram Executive Office for Aircraft Carriers, in particular BrianPersons, deputy program executive officer We also appreciate theefforts made by CAPT Dudley Berthold, former CVN 21 programmanager; CAPT Mike Schwartz, current CVN 21 program manager;and CDR Chris Meyer, assistant program manager At the NavalNuclear Propulsion Program (NAVSEA 08), Robert Murphy andKaren Henneberger contributed to our endeavors Kenneth Dieter atNUWC provided the data for Appendix C on the cost of carriermaintenance availabilities and answered our queries regarding itsinterpretation

We are grateful to Dan Burton, who acted as our facilitator andinterface at Northrop Grumman Newport News We also receivedvaluable assistance there from Matthew Mulherin, vice president forthe CVN 21 program

Max Buzard at Royer Technical Services played a key role inthat firm’s execution of a subcontract for RAND related to theamount of outsourcing possible on future carriers Anne Wolpert ofTecnico Corporation contributed to providing cost estimates forsubcontractor efforts

We owe part of the inspiration for this project to some early culations by our RAND colleague John Halliday We are alsoindebted to our formal reviewers, David Stem of RAND and J Tal-bot Manvel, former director of the CVN 21 program at the Naval

cal-xxiv Modernizing the U.S Aircraft Carrier Fleet

Sea Systems Command, both of whose comments instigated cant improvements to this report

Abbreviations

24/71 24-month production interval, last RCOH on

CVN 7124/72 24-month production interval, last RCOH on

CVN 7230/71 30-month production interval, last RCOH on

CVN 7130/72 30-month production interval, last RCOH on

CVN 72

CVN Carrier vessel, nuclear

CVN 21 Next CVN class (following Nimitz)

CVNX Superseded designation for CVN 21

DPIA Docking planned incremental availabilityEMALS Electromagnetic Aircraft Launch SystemFPRA Forward-Price Rate Agreement

G&A General and administrative

HM&E Hull, mechanical, and electrical

IMP Incremental Maintenance Plan

xxvi Modernizing the U.S Aircraft Carrier Fleet

NAVSEA Naval Sea Systems Command

O&I Organizational and intermediate

OMB Office of Management and BudgetO&MN Operations and Maintenance, NavyOPNAV Office of the Chief of Naval Operations

PIA Planned incremental availability

PSA Post-shakedown availability

RCOH Refueling and complex overhaul

well before the Nimitz class retires Furthermore, with

moderniza-tions undertaken over the years, the ships’ weight has increased andtheir center of gravity has risen (i.e., worsened) to the point where

further increases in topside weight are unacceptable The Nimitz

class’s weapon-handling systems and flight deck were designed withtactical nuclear weapons in mind and are optimized neither for highrates of sortie generation nor for the variety of smart weapons coming

into the inventory Finally, the Nimitz-class Incremental

Mainte-nance Plan requires substantial periods of time in shipyard nance

mainte-The U.S Navy is currently designing the next generation of

air-craft carriers, the CVN 21 class, which will improve on Nimitz-class

capabilities Although it will use the same basic hull form as the

Nimitz, the CVN 21 class will include dramatic improvements to the

ship’s power-generating capability and electrical distribution Thesenew systems will be sufficient for EMALS, which will be installed on

2 Modernizing the U.S Aircraft Carrier Fleet

the first of class and will have enough reserve capacity for advanceddefensive systems that could be added later The layout of the flightdeck will be improved: the island will be moved and elevators for air-craft and weapons relocated There will be a substantial redesign ofthe interior of the ship for improved weapons handling and storesmanagement functions All these improvements are designed with thecharge to significantly reduce manning and maintenance costs,increase operational availability, and minimize maintenance periods.(For details of the improvements included in or allowed by the CVN

21 design, see Appendix A.)

The current Navy plan is to replace Nimitz-class ships as they

reach retirement age—i.e., as they exhaust the nuclear fuel supplied

in their midlife reactor core replenishment Under that plan, the

car-rier fleet will consist mostly of Nimitz-class ships until the 2030s and some Nimitz-class ships will be operating after 2050.

Recognizing the increased operational capabilities and reducedownership costs of the CVN 21 class, the Program Executive Office(PEO) for Aircraft Carriers asked RAND to identify and evaluateoptions that would more quickly transform the carrier fleet to thenew class In conducting the research, we addressed the followingquestions:

• What options are available to introduce CVN 21–class ships at

an accelerated rate? What if Nimitz-class ships were replaced at

midlife instead of being refueled? How do the options affect thenumber of carriers in the fleet and the number available foroperations (i.e., not in the shipyard for maintenance)? (SeeChapter Two.)

• How must the carrier industrial base change to accommodatethe accelerated transformation options? (See Chapter Three.)

• How much more will it cost to replace Nimitz-class ships at

midlife than it would to refuel them? How might the acquisitioncost of CVN 21–class carriers be reduced to make acceleratedmodernization more attractive? (See Chapter Four.)

Introduction 3

To address these questions, we worked closely with the CVN 21program office, the Nuclear Propulsion Directorate (SEA 08) of theNaval Sea Systems Command (NAVSEA), Northrop GrummanNewport News (or NGNN—the only U.S shipbuilder capable ofbuilding nuclear aircraft carriers), and the various nuclear and non-nuclear vendors that support aircraft carrier construction We identi-fied and collected various cost data and factors and constructionworkload profiles for the CVN 21 ships as well as for other ship con-struction and repair projects at NGNN We used these various data

in life-cycle cost (LCC) and industrial base models we created ormodified to assist in our analysis

Fleet Modernization Options and Their

Implications for Fleet Size and Composition

The Navy’s present plan calls for constructing one new CVN 21–class carrier about every four years, thus requiring nearly 50 years tocompletely replace the current fleet of 12 ships In this chapter, wedescribe options that would result in much faster modernization ofthe fleet and examine how those options would affect the fleet sizeand composition over the next several decades The costs of the pro-posed new options are dealt with in Chapters Three and Four Theanalysis presented in this chapter is in three parts:

• We first describe in some detail the present policy and show the

consequent fleet replacement schedule This is the reference case

that will be used as a point of comparison for alternative fleetmodernization options

• We next describe an alternative strategy based on the notion of

retiring some of the older Nimitz-class carriers after about 23

years of service, and replacing them with new CVN 21–class

ships at that time This is the nominal build-new strategy We

show the resulting pattern of fleet composition over time andcompare that with the reference case

• Finally, we explore the fleet size and composition implications ofsome variations on the build-new strategy, in an attempt toachieve a similar modernization rate while reducing costs

6 Modernizing the U.S Aircraft Carrier Fleet

Today’s Policy: The Reference Case

The present fleet of aircraft carriers consists of 12 ships The exactnumber of active ships might fluctuate slightly because the commis-sioning of a new ship does not always coincide exactly with retire-ment of another ship, but the Navy strives to maintain carrier fleetsize at about 12 ships to meet National Security needs To project theevolution of this fleet over the next 50 years, we need three types ofdata: the composition of the current fleet, plans for taking ships out

of service for maintenance (so we can estimate an operational fleet),and a protocol for ship starts and retirements in the coming decades.The composition of the present fleet is summarized in Table 2.1 Theother two items are taken up in each of the next two subsections

Scheduled Refueling and Maintenance

The service life of nuclear-powered ships is determined largely by the

operating life of the reactor core The cores for Nimitz-class ships are

refueled during the midlife complex overhaul These refueling andcomplex overhauls (called “RCOHs”) are a major activity that repairsand modernizes the carrier for the next 23 years of service life The

Current jected Retire- ment Date

Pro-Age at Projected Retirement

Fleet Modernization Options and Implications for Fleet Size and Composition 7

entire operation requires about three years in the shipyard, which isnot dictated by the time it takes to refuel these ships but rather by thesum of maintenance, modernization, and repair that is required dur-

ing this maintenance period The Enterprise was the first

nuclear-powered aircraft carrier, and its nuclear cores have been replenishedthree times in order to extend its operational life to more than 50years

The Nimitz-class ships have a reactor design that was somewhat improved over that of the Enterprise The original expectation was

that the core would sustain operations for about 13 years before

refu-eling When the Nimitz (the first of its class) was started, the plan

called for an expected total operational life of about 30 years, sisting of two 13-year operational periods plus one midlife RCOH ofabout three years duration However, experience with the early

con-Nimitz-class ships indicated that the core life could be extended to as

much as 22 to 23 years, assuming a normal operations tempo Thus

the overall lifespan of a Nimitz-class ship is now expected to typically

consist of about 23 years of operation, followed by an RCOH ofthree years, and then another 23 years of operation, yielding a nomi-nal total life of about 49 years Those rough planning factors led tothe currently-projected schedules shown in Table 2.1

In addition to a midlife RCOH, an aircraft carrier undergoesseveral other scheduled periods of maintenance in the shipyard

(referred to as availabilities) The Nimitz-class carriers’ Incremental

Maintenance Plan (IMP) calls for two kinds of availabilities: aPlanned Incremental Availability (PIA) and a Docking PlannedIncremental Availability (DPIA) (NAVSEA, 1997) A PIA

is a ship depot availability of approximately six months duration that restores or maintains material condition and incrementally significantly modernizes the warfighting capabilities to meet cur- rent and projected threats.

[DPIAs] are overhaul-like in that they restore the ship to established performance standards In addition to the work accomplished during a PIA, a DPIA provides a window during which required underwater maintenance is accomplished The

8 Modernizing the U.S Aircraft Carrier Fleet

DPIA also provides sufficient time to perform more extensive propulsion plant repairs and testing than is possible during the PIA.

A typical DPIA requires ten to eleven months in the shipyard Thenominal plan assumes an operational period of about 18 monthsbetween availabilities.1

The IMP-prescribed life cycle of a Nimitz-class carrier is shown

in Figure 2.1 After the ship is commissioned there is a shakedowncruise, followed by a Post-Shakedown Availability (PSA) assessment

to repair any discrepancies discovered and to complete any tion and outfitting activities that had been deferred during the origi-nal construction period That shakedown cruise, and correspondingPSA, typically lasts about a year, after which the ship is ready foroperational duty During the following two decades, the ship operatesfor 18 to 20 months at sea, training and deploying as needed, fol-lowed by a PIA or a DPIA during which necessary maintenanceactions are performed After 23 years, the reactor needs to be refueled

construc-We show the life cycle in Figure 2.1 as we understand it fromthe IMP However, when the 18-month operating periods and theprescribed availabilities at their nominal lengths are added up, theduration prior to refueling comes to 25.6 years To resolve the dis-crepancy, we took the 23-year refueling interval as correct andadjusted the maintenance protocol to agree with it Specifically, wedeleted one PIA from each of two intervals between DPIAs, thusleaving two operating periods in each of those intervals, and we

1 After the research described in this report was completed, the Navy began to investigate different maintenance plans intended to enable the carriers to sustain a longer period of operations between shipyard availabilities, thereby increasing their responsiveness to opera- tional demands If such revised maintenance schedules are implemented, it might change in some detail the conclusions reached in this report However, as of publication date no spe- cific plan had emerged, and no attempt was made to incorporate such revisions in our analy- sis Furthermore, it is our understanding that any revision in carrier maintenance plan would not reduce the total number of maintenance man-hours required during the carrier’s life It seems unlikely that implementation of such a plan would significantly change the conclu- sions presented in this report.

Fleet Modernization Options and Implications for Fleet Size and Composition 9

assumed that all operating periods were 19.5 months Operatingperiods of that length conform in the aggregate to recent experience,and yield a slightly higher fraction of the time the ship is in an opera-tional deployment compared with the IMP Thus, it does not in anyway penalize the “reference case” in comparison with the build-newoptions examined here

We assume that the second half of the carrier life, after the life RCOH, will follow the same pattern as the first half, except thatthe shakedown cruise and PSA is expected to last only 10 months

mid-(There is little experience with the second half of a Nimitz carrier’s life The Nimitz came out of its RCOH in 2001.) The ship’s life ends

with decommissioning, deactivation of the reactor, and disposal ofthat and the rest of the ship.2

With the retirement of the Constellation (CV 64) and the tion of the Ronald Reagan (CVN 76), the fleet now consists of nine

activa-Nimitz-class ships and three earlier models When the George H W Bush replaces the Kitty Hawk, the Nimitz program will be complete.

The present plan is to introduce a new carrier design, the CVN 21

2 We include these activities in our cost analysis in Chapter Four We do not include them

in the labor demand analysis in Chapter Three or in the fleet replacement protocol in this chapter Decommissioning and deactivation could make demands on NGNN facilities that might compete with construction or RCOHs However, it is unlikely that disposal will be accomplished at NGNN and uncertain whether nuclear deactivation will Such activities could require nontrivial dedication of shipyard resources.

10 Modernizing the U.S Aircraft Carrier Fleet

class described above (see also Appendix A), with construction ing in 2007 and first delivery in 2014 That ship is now expected to

start-require far less maintenance than the Nimitz-class, with longer

peri-ods of operation between shipyard availabilities The current jection of the CVN 21 life cycle is shown in Figure 2.2, with the

pro-information for the Nimitz-class carriers repeated for convenience Note that a Nimitz-class aircraft carrier spends considerable time

in the shipyard—one-third of its life, from commissioning to missioning As shown in Figure 2.2, one of the major differences

decom-between the Nimitz-class ships and the CVN 21–class ships is that

the new model is projected to require considerably less time in theshipyard and thus will be available for operational use during a largerfraction of its life

Figure 2.2

Comparison of Nimitz-Class and CVN 21 Life Spans

Ship commissioned

Nimitz-class IMP schedule

PSA PIA DPIA

About 23 years

Decommission RCOH

Ship commissioned

CVN 21 schedule

About 22 years

Decommission RCOH

Fleet Modernization Options and Implications for Fleet Size and Composition 11

Fleet Composition and Size

Given the data from Table 2.1 and Figure 2.2, we can predict a ence case fleet composition if we can project a schedule of new startsfor the CVN 21 class Assuming a nominal lifetime of each ship ofabout 49 years, to maintain a fleet of 12 ships requires that a newship be built at intervals of about four years However, Table 2.1illustrates that the schedule of construction starts for the present fleethas been quite uneven Ships were built in rapid succession in the1960s (four were launched in a span of seven years), while the mostrecent two were launched at intervals of five years each The nominalpractice of building a new ship when needed to replace a retired shipleads to a very uneven production schedule, with attendant industrialinefficiencies In our projection of future actions in the reference case,

refer-we assume that the CVN 21 ships will be produced at regular year intervals, starting with the first delivery in September 2014.The resulting schedule of fleet composition projected for the2000–2050 time period is depicted in Figure 2.3.3 Here we showonly the major activities: construction followed by a shakedowncruise and PSA; the initial 22- to 23-year operational period; theRCOH (three years plus 10 months shakedown and PSA); and thesecond operational period, followed by decommissioning It can beseen that this does not result in a perfect match of ship commission-ing on the same date that an older ship is retired, but deviations from

four-a constfour-ant 12-ship fleet size four-are slight

To compare the different fleet modernization options, we mustestablish some measures of merit that can be consistently applied andthat would reflect the relative value of each option to the Navy Interms of fleet size and composition, we will focus on three aggregate

measures: the rate at which the older Nimitz-class ships are replaced

with CVN 21–class ships; the overall size of the fleet, expressed as

average total inventory over the course of each year; and the number of

ships that are not undergoing shipyard maintenance or overhaul, and

3 Here, as elsewhere, we use CVX followed by a hull number to denote the CVN 21–class ships We cut the projection off at 2050—near our cost estimation cutoff Thus, only the first 10 ships of the planned 12-ship CVN 21 program are shown.

12 Modernizing the U.S Aircraft Carrier Fleet

thus are operationally available, averaged over the course of each year.

These measures have the advantage of being quantitative and tively easy to estimate

rela-Under the schedule shown in Figure 2.3, the last Nimitz-class

ship, CVN 77, is not replaced until the late 2050s The replacementprofile is depicted in Figure 2.4

The average inventory of carriers in any year for the referencecase is shown in Figure 2.5, compared with the average number ofships available for operations during that year The reference case sus-tains the Navy’s target inventory of 12 ships, with about eight ofthose in operational status at any one time.4

In-service post-RCOH RCOH

In-service pre-RCOH PSA

Build

4 The minor fluctuations from one year to the next are a consequence of the uneven intervals between historical construction starts for the present fleet and our assumed four-year new- start interval for CVN 21–class ships to replace the older carriers.